rakkhana : [nt.] protection; observance.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]

Rakkhana (nt.) [fr. rakkh] 1. keeping, protection, guarding Nett 41; Mhvs 35, 72 (rahassa˚ -- atthāya so that he should keep the secret); PvA 7. -- 2. observance, keeping VvA 71 (uposatha -- sīla˚); PvA 102 (sīla˚), 210 (uposatha˚).

Pali-English Dictionary, TW Rhys Davids, William Stede,